Set Your Refrigerator to the Warmest Setting (26/365)

Let’s cut straight to the chase. The sweet spot for any refrigerator is between 39 and 40 F. This is the temperature at which bacterial growth is inhibited but the difference between your refrigerator and the ambient temperature outside of your refrigerator is minimized.

Your refrigerator is one of the biggest power guzzlers in your house. Over the course of a year, a modern refrigerator sucks down about 350 kWh of energy. That adds up to about $50. With a few simple one-time changes taking just a few minutes, though, you can cut that by about 20%, saving you $10 a year for as long as you own the fridge.

First of all, most refrigerators have a terrible internal dial that doesn’t indicate actual temperatures. I loathe this design “feature.” It doesn’t tell you a thing about the actual internal temperature of your fridge. It merely compares it to other settings.

The simple solution? Get an inexpensive thermometer and stick it in your fridge. You can get a small digital thermometer at your local hardware store for a pittance. Just tape it somewhere to the inside of your refrigerator. I just rolled up a bit of duct tape and stuck it to the back of one for placement inside of the refrigerator.

Then, start playing with that dial. I suggest moving slowly downward, then checking the temperature every day. What you’re looking for is a temperature close to 38.5 or 39, at which point you’re going to want to stop on that setting for a while. For most refrigerators, this temperature coincides with the lowest setting or one of the lowest settings.

It’s important to remember that the temperature isn’t an exact thing. A refrigerator works just like your home. It tries to keep the temperature within a degree or so of the ideal temperature. This is why you should stop adjusting the temperature dial for a while if you observe a temperature around 38.5 or 39 degrees, as this may be a “low” temperature, a “high” temperature, or an average one. Do some observations over time and see what the average is.

I would shoot for an average of around 38.8 to 39 F, so that the “high” temperature doesn’t break 40 F very often.

Also, pay attention to where the fan is in your refrigerator. The air coming in there is going to be cold air, so the items near it are going to be colder than items elsewhere in the refrigerator. We generally keep items that we worry the most about spoiling close to the fan (items such as milk and eggs) and other items further away. I placed the temperature gauge on the other side of the refrigerator interior from the fan to try to get more of an ambient temperature. Also, never block the fan. Always make sure the fan can blow cold air into the interior of your refrigerator. If you block it, you’ll have one frozen item and a bunch of warm items in your fridge.

If your refrigerator is really full with items, lower the temperature a bit. Lots of items means poor air flow inside of your refrigerator, which is the key to keeping things cool. Lowering the temperature means you’re going to be using a bit more energy, but all of your items are cold. We do this when we’re prepping for a party or something similar.

What about the freezer? You want your freezer to be low enough so that temperature variation does not allow anything to melt in the freezer. I suggest keeping the freezer at a temperature around 5 F – and a bit lower than that if your freezer is jam-packed with stuff, blocking the air flow. You can check this with a thermometer taped to the side away from the fan, just like with the refrigerator.

Another useful tactic is to thaw frozen foods in the fridge instead of on the counter. As frozen foods thaw, they cool the air around them. This is a good thing in a refrigerator that you want to keep cool internally. It’s a bad thing most of the time outside of the refrigerator, as it’s not going to provide a significant enough effect to keep your air conditioner from running any significant amount and it’s going to work in a small way against your furnace.

Once the temperature is set correctly on your refrigerator and freezer, and you’re using the device sensibly (not blocking the air flow, thawing foods in the refrigerator, etc.), your refrigerator is going to use less energy. It’s also not going to have to work as hard, extending its lifespan. Both of these save you money, as your monthly energy bill is reduced and the time until your next refrigerator replacement is extended.

Interesting, never knew about the 39 to 40 degree optimal range. Thanks for sharing that.

Good bigger point about how household appliances can consume a fair amount of energy through the course of the year – meaning a fair amount of money spent! A few tweaks here and there in terms of settings and usage patterns can create savings that add up.

I think Trent’s right and spoilage is a minimal risk in these experiments. Okay, I won’t say there’s no risk, but the fact is that we tend to give ourselves a wide margin of error on food spoilage culturally. In most of the world, people store eggs at room temperature without a problem; they’re not going to go bad because they were at 41 degrees for a few hours.

Is it bad that every time I read the title of a new post, I actually say “Are you SERIOUS???”

I have gained much valuable information from this blog (including an intro to cloth diapers, which I now make and sell as an at-home business). I hesitate to criticize this blog because I really do appreciate a lot of the posts in the archives.

I would be careful to pick the warmer spots of the refrigerator for your thermometer, like the inside of the door. This one to me is not worth the risk of food spoilage.

I agree with Lilly that this series is a bit silly in a lot of cases. I guess the point is that if you do all 365 of these things you can save some decent money, but taken individually, most of them hardly seem worth the effort.

A few years ago, the (state-owned) power company in my area had a program to help people get rid of their old refrigerators. The stated reason was that old fridges (10-plus years old) are less energy-efficient.

I suspect that the cost of use for a refrigerator (and therefore the savings per degree reduced)varies greatly according to the model, size and age of the appliance (I have friends whose fridge is twice the size of mine). So the 10$ savings / year may be underestimated for some, but the equivalent of splitting hairs for others.

Buying a less energy-consuming model up front may be the wiser choice here.

@Katie: I don’t know about eggs (I don’t cook with them, myself), but I have noticed that things like fruits, vegetables, and leftovers don’t last as long as I’d like when I have the refrigerator on a warmer setting.

That’s why I keep my refrigerator on the coldest setting (unless I have a problem with things freezing, which with my current fridge I don’t). I’ll pay an extra $10/year for electricity if it means I don’t have to throw things out as often.

The two biggests energy users in a household are heat/AC and the water heater, refrigeration is far below those two. A late model refrigerator only uses between one and two dollars worth of electricity each week.

The warmest spot in my refrigerator is where we keep the milk. Having the milk spoil before it’s time negates any savings from monkeying around for some magic temperature. I pick the setting just a tad warmer than where the milk freezes. No experimentation with a thermometer required, the freeze factor is good enough. My electric bill remains quite affordable even though the dishwasher is right next to the fridge.

No, thanks. If there’s a power failure lasting several hours, I’d prefer not to have to second guess the contents of my refrigerator. I’ve had food poisoning; to avoid having it again, I’ll let the fridge stay a bit colder than it has to be.

Why not just turn the refrigerator off altogether for part of the year? In Iowa, it is very cold for several months, so your frozen food would stay frozen if you simply keep it outside. For the milk and everything else in the fridge, you would simply experiment until you find a spot in your garage that is the right temperature. Save even more money!

I follow America’s Test Kitchen guidance pretty much to the letter. They state to keep your fridge between 33-39 degrees, and the freezer should be at 0. I bought a couple of inexpensive NSF-approved thermometers (one for fridge/freezer and one for the oven) to verify my settings. If you do much cooking/baking, verifying your oven temps is a good idea–I find my oven ranges about 25 degrees higher than the dial.

My refrigerator has an actual temperature setting in degrees on the outside. From memory, I believe they suggest 37F in the fridge and 0F in the freezer.

Based on the information Trent linked to, I’d be hesitant to be too close to the 40F mark (the start of the “Danger Zone”):

“Pathogenic bacteria can grow rapidly in the “Danger Zone,” the temperature range between 40 and 140 °F, but they do not generally affect the taste, smell, or appearance of a food. In other words, one cannot tell that a pathogen is present.”

#7 Izabelle is right, that older fridges are much worse. A 30 year old fridge could easily use $250 a year instead of $50 a year. The model and size etc, will matter as well but not as much. Of all the fridges on the EnergyStar site the range is around $32-$79 per year of electric use.

I can’t believe you even mentioned the possibility of thawing food out of the fridge and it perhaps having a tiny effect on your furnace. What is the next tip, “Stop using ice in beverages in winter to help save your furnace”???

#20 liz – I had just scanned the article & read the highlighted sentences. I’m flabbergasted that even Trent would discuss the impact of thawing food on the room temperature. Now this series really is getting ridiculous. Better not eat warm food in the summer or anything cool in the winter if you’re really serious about living cheap.

we keep our refrigerator in our new apartment quite cold. Not cold enough for anything to freeze. We have noticed a HUGE increase in the life of our food. Milk stays fresh a WEEK longer. Everything just lasts and lasts and lasts. Plus all our drinks are nice and icy.

I think you’ve missed the biggest energy saver with your fridge – keeping the door closed as much as possible. When you open the door a bunch of the cold air rushes out (worse for freezer on the bottom models) and the fridge has to use extra energy to cool itself again.

Know what you want before you open the door. Don’t just stand there and think about what you might want. It can help to have a list on the outside of the door (a whiteboard is good for this) of what foods you have in there. You don’t open your front door in winter and stand there letting cold air in while you decide where to go.

Have all the cold ingredients you need for a meal in your mind before you reach in there, then get them all out at once and close the door.

This series seems to really go to the extremes. Some ideas are good, some are good but I’ll never do, and some are just…extreme. Power to the frugalites who can stand to live that extreme by choice! (I know, some people have to go to extremes at times, and that is perfectly fine.)

On another note, my advice if you try this tip is to make sure you have a decent fridge to begin with… Has anyone had trouble with Magic Chef fridges freezing AND keeping food too warm…at the same time? I’ve had experience with 3-4 of the stupid things and all of them have had the same problem. It’s much worse in the summertime, and even the brand new fridge did the same thing! Can’t wait until I’ve saved up enough to purchase a new, non-magic chef fridge…

I pay around 5.4 cents for the first 30 kWh and 7.5 cents for anything above in the same month, but the climate here is very cold so a LOT goes to heating. Still 50$ is less than 4% of my yearly bill, hence my comment.

The best energy-saving tip I have is to make sure your heating system is up to date. We changed ours 3 years ago, and the reduction in heating costs paid for the switch in 2 years. Anything after that is money in the bank!

And the savings for the heating system switch from oil to electricity (once all was paid) is to the order of 3000-3500$ per year for a medium-size detached house. To give an idea of climate, we are about 1 hour north of the Vermont border (so pretty cold). Definitely our strongest saving strategy so far :)

I’m surprised nobody has mentioned keeping drinks cold – soda in particular. The difference between enjoying soda and not, for me, is that last few degrees before it gets slushy. And as a few have mentioned, I suspect that generally the amount of time the door spends open has a FAR greater impact on your electric bill over time than the temperature setting.

Anything between 32 and 39 F is fine for food. We store sensitive lab “biologicals” at 39 F (4 C) and it lasts for quite a long time. Spoilage is going to come mostly from the yeasts and molds in the air, anyway, and there’s nothing you can do about it except to store your food properly, and to reheat it hot enough to kill everything. And, of course, eat it within a certain amount of time.

Bacteria do not grow well at room temperature, and in refrigerators they enter a state of “hibernation”. They grow, but VERY slowly (if at all–I’ve had petri dishes of E. coli in the refrigerator for up to a month, and those colonies never changed). Food handling techniques and proper food safety procedures will go a far longer way towards keeping your food safe than yelling at Trent.

Trent did not suggest that you thaw food on the counter. He is correct about the fact that any cold thing you put into your environment will have an impact on your heating, thermodynamically speaking. I do not see his condemning the frozen chicken for cooling the kitchen as a ringing endorsement for thawing it on the counter.

The problem I have with this article is that it describes fairly insignificant savings in a potentially risky area.

#37 DrFunZ – Can’t wait for Trent’s post detailing the exact percent of a degree change that a thawing casserole has on an air conditioned room vs. a heated room. I don’t remember ever walking past a thawing item on the counter & noticing any change in temp, much less enough change that it would impact how often the ac or heater runs.

#5 Lilly – You took the words right out of my mouth. Really?? This post is all about saving $10 a year in refrigerator energy costs at the risk of food spoilage? If you keep your refrigerator at 39 degrees and open it several times each day…do you really think your food is going be maintained in the safe range? Sorry, but as this series progresses, I am losing faith in Trent’s advice faster than I can turn my fridge’s thermostat up to 40 degrees.

Books worth budgeting for

My new book, The Simple Dollar: How One Man Wiped Out His Debts and Achieved the Life of His Dreams, is available in bookstores now. Check out some of the life-changing experiences the book has given readers!

Check out my book, 365 Ways to Live Cheap, available in bookstores everywhere! It's filled with 365 great tactics you can apply to your personal finances, from frugal tips to great ideas for managing your money.